Investigation on the Stability of Derivative Melam from Melamine Pyrolysis under High Pressure

Although various kinds of carbon nitride precursors have been proposed, s-triazine-based structures are hardly reported because of their unfavorable energy, higher than that of heptazine-based ones. In this study, we investigate the thermal stability of s-triazine-based melam processed at a high pressure of 5 GPa and a temperature of 400–700 °C and complete the analyses of the composition and structure of the treated samples through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and elemental analyses (EA). Results show that melam can stably exist up to 600 °C at 5 GPa. XRD and FTIR analyses reveal that residual melamine can be pyrolyzed into melam as temperature increases from 400 °C to 600 °C at a high pressure, suggesting that melam may be purified through high-pressure pyrolysis. Further melam polymerization at a higher pressure is a promising strategy for the preparation of s-triazine-based carbon nitride precursors used for bulk carbon nitride synthesis

A secure routing model based on distance vector routing algorithm

Distance vector routing protocols have been widely adopted as an efficient routing mechanism in current Internet, and any wireless networks. However, as is well-known, the existing distance vector routing protocols are insecure as it lacks of effective authorization mechanisms and routing updates aggregated from other routers. As a result, the network routing-based attacks become a critical issue which could lead to a more deteriorate performance than other general network attacks. To efficiently address this issue, this paper, through analyzing the routing model and its security aspect, and presents a novel approach on guaranteeing the routing security. Based on the model, we present the security mechanism including the message exchange and update message security authentication mechanism. The suggested approach shows that the security mechanism can effectively verify the integrity and validate the freshness of routing update messages received from neighbor nodes. In comparison with exiting mechanisms (SDV, S-RIP etc), the proposed model provides enhanced security without introducing significant network overheads and complexity

Investigation on the Basic Characteristics of Semi-Fixed Abrasive Grains Polishing Technique for Polishing Sapphire (α-Al₂O₃)

Single-crystal sapphire (α-Al2O3) is an important material and widely used in many advanced fields. The semi-fixed abrasive grain processing method based on solid-phase reaction theory is a prominent processing method for achieving ultra-precision damage-free surfaces. In order to develop the proposed method for polishing sapphire, the basic characteristics of the semi-fixed abrasive grains polishing tool for polishing sapphire were determined. Weight analysis was used to study the influence rules of parameters on surface roughness and material removal rates using an orthogonal experiment. Then, the optimized polishing tool was obtained through a mixture of abrasive particle sizes to reduce the difficulty in molding the polishing tool. Finally, polishing experiments using different polishing tools were carried out to investigate polishing performance by considering the surface roughness, material removal rate and the surface morphology during polishing. The results showed that (1) external load affects the surface roughness and material removal rate the most, followed by abrasive particle size, sand bond ratio, revolution speed of the workpiece and he polishing tool; (2) the difficulty in manufacturing the polishing tool could be reduced by mixing larger abrasive particles with small abrasive particles; (3) the polishing tool with 200 nm and 1 μm particle sizes performed best in the first 210 min polishing

Association of the controlling nutritional status score with all-cause mortality and cancer mortality risk in patients with type 2 diabetes: NHANES 1999–2018

Abstract Objective There are studies on the nutritional status of type 2 diabetes (T2D), but there are no large cohort studies on the prognosis of Controlling Nutritional Status (CONUT) score for T2D. The aim of this study was to examine the association between CONUT score and all-cause mortality as well as cancer mortality in adults with T2D. Methods For this study, we analyzed a total of 3763 adult patients with T2D who were part of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Mortality outcomes were determined by linking to the National Death Index records as of December 31, 2019. Cox proportional risk models were used to estimate risk ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cancer deaths. Results During the mean follow-up of 8.17 years, there were 823 deaths from all causes and 155 deaths from cancer. After adjusting for multiple variables, the risk of all-cause mortality was higher in patients with a Mild (CONUT score ≥ 2), compared with patients with a Normal (CONUT score of 0–1). All-cause mortality risk was 39% higher, and cancer mortality risk was 45% higher. Consistent results were observed when stratified by age, sex, race, BMI, smoking status, and glycated hemoglobin levels. Conclusions In a nationally representative sample of American adults with T2D, we found an association between CONUT score and all-cause mortality and cancer mortality

Navigating the future of diabetes: innovative nomogram models for predicting all-cause mortality risk in diabetic nephropathy

Abstract Objective This study aims to establish and validate a nomogram model for the all-cause mortality rate in patients with diabetic nephropathy (DN). Methods We analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2016. A random split of 7:3 was performed between the training and validation sets. Utilizing follow-up data until December 31, 2019, we examined the all-cause mortality rate. Cox regression models and Least Absolute Shrinkage and Selection Operator (LASSO) regression models were employed in the training cohort to develop a nomogram for predicting all-cause mortality in the studied population. Finally, various validation methods were employed to assess the predictive performance of the nomogram, and Decision Curve Analysis (DCA) was conducted to evaluate the clinical utility of the nomogram. Results After the results of LASSO regression models and Cox multivariate analyses, a total of 8 variables were selected, gender, age, poverty income ratio, heart failure, body mass index, albumin, blood urea nitrogen and serum uric acid. A nomogram model was built based on these predictors. The C-index values in training cohort of 3-year, 5-year, 10-year mortality rates were 0.820, 0.807, and 0.798. In the validation cohort, the C-index values of 3-year, 5-year, 10-year mortality rates were 0.773, 0.788, and 0.817, respectively. The calibration curve demonstrates satisfactory consistency between the two cohorts. Conclusion The newly developed nomogram proves to be effective in predicting the all-cause mortality risk in patients with diabetic nephropathy, and it has undergone robust internal validation